Patent GB-400735-A (GB)
Title: Improvements in or relating to aircraft
IPC: B64C23/00
Filed: 1932-07-22
Abstract: 400,735. Aeroplanes. BOLAS, H. and CROUCH, R. J. G., P.O. Box 375, Pawtucket, Rhode Island, U.S.A. July 22, 1932, No. 20744. Convention date, Dec. 31, 1931, [Class 4.] An aircraft having a wing provided with means for varying its aerodynamic characteristics and a tail control surface rearwardly of the wing has the axis of the airscrew, or each airscrew, set at such an angle to the chord of the main body of the wing that when the airscrew axis is horizontal the main body of the wing has a positive angle of incidence throughout its length and a slip stream is developed substantially enveloping the whole of the wing and tail control surface. In one form, Figs. 7 and 8, four engines driving variable pitch airscrews are arranged along the wing so that the slipstream envelopes substantially the whole of the lifting surface. The wings have flaps 43, 44 of which the latter may be operated differentially. The engines are adjustably mounted and may be tilted, by rack and pinion means, for low-speed flight from a position in which the airscrew axes make a small positive angle of incidence with the planes to the position shewn. With the engines in this position the flaps are pulled downwards and pilot planes 42 or similar devices become operative. Elevator 39, rudders 41, and fins 40 are disposed so as always to be in the propeller slipstream. In the case of a bi-plane the engines are mounted above the lower planes. In a modification, Fig. 12, a wing unit comprising biplane wings 50 and engines 53 is connected by tail-booms 55 to a tail-unit of the type shewn in Fig. 7, and is pivoted to a fuselage 67 by means of brackets 76, Fig. 15, secured to the front spar of the lower wing and journalled on a shaft 68 mounted in the fuselage. The fuselage is slotted as shewn to allow for movement of the rear spar and flap control rods. The planes are fitted with automatic pilot planes 60, 61 and slotted flaps 64, 65, Fig. 16, of which the outer are differentially operable. Relative movement between body and wings is effected by hydraulic means, Fig. 15, comprising cylinders 80 in which work pistons 82 having rods 81 connected to the rear spar of the lower plane. Oil can be drawn from the upper portions of the cylinders and delivered to the lower portions thereof, and vice versa, dependant upon the position of a four-way cock 85, by means of a double-acting hand pump 83. A reservoir 84 is provided to allow for the change in volume of the oil circulated due to the lower capacity of the piston rod ends of cylinders 80 compared with their lower ends. The cock 85 can be set to maintain the pistons 82 stationary. Flap actuation is automatically effected by downward tilting of the wing unit. Flap control rods 95, 102, Fig. 16, are connected to independent bell-crank levers 93, 101, 101 mounted on a vertical spindle centrally of the wing. Bell crank lever 93 has one end connected to rod 95 operating to inner flaps and the other connected to a lover 91 on shaft 68. Since its point of connection on lever 91 is not co-axial with the swinging axis 68 of the wing, downward movement of the latter causes rocking of the bell-crank lever 93 to operate the flaps. The outer flaps are similarly operated by connections from bell-cranks 101 to bell-crank levers 99 but these are in addition capable of differential movement by being linked to a lever 107 on a torsion rod 108 of the hand control 109. As shewn in Fig. 12 the engines, which have geared propellers, are fixed with the airscrew axis downwardly inclined but means may be provided for automatically altering the line of action of the screw. As shewn in Fig. 17 an engine 111 is connected to a mounting 112 at four points, the two lower points 113 constituting a hinging axis. Elastic members 114 with internal springs 115 provide the upper connection. The arrangement is such that at low speeds with increased airscrew thrust the downward tilt of the engine relative to the wings increases. In a modification providing for positive actuation, the engine is hingedly mounted at upper attachment points and the lower points are connected by a link to a crank on a transverse shaft having a pinion engaged by a rack secured to the body so that movement of the wings relatively to the body causes rotation of the pinion and adjustment of the airscrew axis. The crank shaft turns through 180‹ and is arranged so that the link and crank are on dead centres in the two limiting positions. Alteration of airscrew pitch is effected by relative movement between wings and body connections comprising links 127, Fig. 16, bell-cranks 128 and links 129 transmit movement of the inner flap operating rod to a twoway cock 126 acting on the oil system effecting pitch adjustment. With a movable engine mounting the cock 126 is linked by a rod to the relatively fixed part of the mounting.